Which of the following signs most strongly supports dehydration in a dehydrated infant with diarrhea?

• A. Teary eyes.
• B. Sunken fontanel.
• C. Normal skin turgor.
• D. Moist mucous membranes.

Answer: (B)

In infants, signs of dehydration are often best read from clues that reflect fluid status, and the fontanel is a sensitive indicator. A sunken anterior fontanel strongly points to dehydration because reduced circulating volume and body water cause the soft spot on the skull to appear recessed. Teary eyes and moist mucous membranes suggest adequate hydration, so they are less supportive of dehydration. Normal skin turgor can be unreliable in very young children, so it’s not as specific a cue as a sunken fontanel. Therefore, the sunken fontanel is the most informative sign for dehydration in an infant with diarrhea.